The present invention relates to a method of producing a tight joint between a thermally fusible multi-layer synthetic resin material and a fluid-permeable filter medium. In addition, the present invention relates to a filter element produced by the method of the invention.
A method of the type defined above is disclosed in German patent publication no. DE 199 19 289. In this method, the layer of the synthetic resin material that is to be heated contains inductively heatable particles which are heated by induction before the joining operation and thus cause the synthetic resin material to melt.
One disadvantage of this method is that an inductive energy source must be made available and properly adjusted. In addition, it is impossible to produce a metal-free filter element by this method because the inductively heatable particles necessarily contain metal.